imo Dawn of war 2 (and expansions) follwed by Dawn of war 1 (and add one) are the best RTS game
company of heroes is also a solid choice
i cant speak for the first one as i have oposing fronts but it is very good.
world in conflict is supposed to be extremely solid as well althought i have no exp with it
Like linkin said, definitely look into starcraft II. It has a pretty huge following and active community. I didn't like red alert 3 as much but it was still decent.
Thanks so much for the replies! hmm, seems that the genre is slowing down these days. I tried a couple of Starcraft 2 skirmish on my friend's pc. thought it was quite great. not sure if im up to playing on bnet though. I generally suck at non-fps when it comes to multiplayer
I have red alert 3 and CC3, i have tons of fun LAN-ing with my bro. RA2 is a classic, dont think i have it anymore though.
is there any historical/fantasy RTS? i've tried AOE3, Rome: Total war and a few more which i cant recall right now
AOE2 was awesome. I suggest you take a look at it. Age of Mythology was positively EPIC.